Numerous studies have shown that maternal age, race, martial status, and birth order are associated with differences in risk of infant mortality, often in complex ways. For example, unwed mothers generally are at greater risk, but among Blacks there is no difference in risk between married and unwed mothers. The purpose of the proposed research is to explain these demographic patterns of pregnancy outcome in terms of social and medical intervening factors. The research will use data from the National Longitudinal Surveys of Work Experience of Youth for the years 1979-84. Social factors to be examined with respect to demographic risk groups include family structure (presence of, and support from, the child's father and other adult kin), family income, personality characteristics (e.g. self-esteem), education, and patterns of child care. Medical factors to be examined include prenatal and pediatric care, mother's prenatal nutrition and use of alcohol and cigarettes, and the infant's nutrition. Outcomes to be examined include birth weight, gestational age, and infant morbidity and mortality. Differences in intervening factors between the demographic risk groups will be described, e.g. do Black married and unwed mothers have similar family structures and income. Regression or logit models will be used to identify which intervening factors are most important in explaining demographic patterns of risk. The results will indicate what specific types of interventions are likely to succeed with different high-risk demographic populations.